developer.intra2net.com Git - libftdi/blob - src/ftdi_stream.c

   1 /***************************************************************************
   2                           ftdi_stream.c  -  description
   3                              -------------------
   4     copyright            : (C) 2009 Micah Dowty 2010 Uwe Bonnes
   5     email                : opensource@intra2net.com
   6  ***************************************************************************/
   7
   8 /***************************************************************************
   9  *                                                                         *
  10  *   This program is free software; you can redistribute it and/or modify  *
  11  *   it under the terms of the GNU Lesser General Public License           *
  12  *   version 2.1 as published by the Free Software Foundation;             *
  13  *                                                                         *
  14  ***************************************************************************/
  15
  16 /* Adapted from
  17  * fastftdi.c - A minimal FTDI FT232H interface for which supports bit-bang
  18  *              mode, but focuses on very high-performance support for
  19  *              synchronous FIFO mode. Requires libusb-1.0
  20  *
  21  * Copyright (C) 2009 Micah Dowty
  22  *
  23  * Permission is hereby granted, free of charge, to any person obtaining a copy
  24  * of this software and associated documentation files (the "Software"), to deal
  25  * in the Software without restriction, including without limitation the rights
  26  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  27  * copies of the Software, and to permit persons to whom the Software is
  28  * furnished to do so, subject to the following conditions:
  29  *
  30  * The above copyright notice and this permission notice shall be included in
  31  * all copies or substantial portions of the Software.
  32  *
  33  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  34  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  35  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  36  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  37  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  38  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  39  * THE SOFTWARE.
  40  */
  41
  42 #include <stdlib.h>
  43 #include <stdio.h>
  44
  45 #include "ftdi.h"
  46
  47 typedef struct
  48 {
  49     FTDIStreamCallback *callback;
  50     void *userdata;
  51     int packetsize;
  52     int activity;
  53     int result;
  54     FTDIProgressInfo progress;
  55 } FTDIStreamState;
  56
  57 /* Handle callbacks
  58  *
  59  * With Exit request, free memory and release the transfer
  60  *
  61  * state->result is only set when some error happens
  62  */
  63 static void
  64 ftdi_readstream_cb(struct libusb_transfer *transfer)
  65 {
  66    FTDIStreamState *state = transfer->user_data;
  67    int packet_size = state->packetsize;
  68
  69    state->activity++;
  70    if (transfer->status == LIBUSB_TRANSFER_COMPLETED)
  71    {
  72        int i;
  73        uint8_t *ptr = transfer->buffer;
  74        int length = transfer->actual_length;
  75        int numPackets = (length + packet_size - 1) / packet_size;
  76        int res;
  77
  78        for (i = 0; i < numPackets; i++)
  79        {
  80            int payloadLen;
  81            int packetLen = length;
  82
  83            if (packetLen > packet_size)
  84                packetLen = packet_size;
  85
  86            payloadLen = packetLen - 2;
  87            state->progress.current.totalBytes += payloadLen;
  88
  89            res = state->callback(ptr + 2, payloadLen,
  90                                  NULL, state->userdata);
  91
  92            ptr += packetLen;
  93            length -= packetLen;
  94        }
  95        if (res)
  96        {
  97            free(transfer->buffer);
  98            libusb_free_transfer(transfer);
  99        }
 100        else
 101        {
 102            transfer->status = -1;
 103            state->result = libusb_submit_transfer(transfer);
 104        }
 105    }
 106    else
 107    {
 108        fprintf(stderr, "unknown status %d\n",transfer->status);
 109        state->result = LIBUSB_ERROR_IO;
 110    }
 111 }
 112
 113 /**
 114    Helper function to calculate (unix) time differences
 115
 116    \param a timeval
 117    \param b timeval
 118 */
 119 static double
 120 TimevalDiff(const struct timeval *a, const struct timeval *b)
 121 {
 122    return (a->tv_sec - b->tv_sec) + 1e-6 * (a->tv_usec - b->tv_usec);
 123 }
 124
 125 /**
 126     Streaming reading of data from the device
 127
 128     Use asynchronous transfers in libusb-1.0 for high-performance
 129     streaming of data from a device interface back to the PC. This
 130     function continuously transfers data until either an error occurs
 131     or the callback returns a nonzero value. This function returns
 132     a libusb error code or the callback's return value.
 133
 134     For every contiguous block of received data, the callback will
 135     be invoked.
 136
 137     \param  ftdi pointer to ftdi_context
 138     \param  callback to user supplied function for one block of data
 139     \param  userdata
 140     \param  packetsPerTransfer number of packets per transfer
 141     \param  numTransfers Number of transfers per callback
 142
 143 */
 144
 145 int
 146 ftdi_readstream(struct ftdi_context *ftdi,
 147                       FTDIStreamCallback *callback, void *userdata,
 148                       int packetsPerTransfer, int numTransfers)
 149 {
 150     struct libusb_transfer **transfers;
 151     FTDIStreamState state = { callback, userdata, ftdi->max_packet_size, 1 };
 152     int bufferSize = packetsPerTransfer * ftdi->max_packet_size;
 153     int xferIndex;
 154     int err = 0;
 155
 156     fprintf(stderr, "ftdi_readstream\n");
 157     /*
 158      * Set up all transfers
 159      */
 160
 161     transfers = calloc(numTransfers, sizeof *transfers);
 162     if (!transfers) {
 163         err = LIBUSB_ERROR_NO_MEM;
 164         goto cleanup;
 165     }
 166
 167     for (xferIndex = 0; xferIndex < numTransfers; xferIndex++)
 168     {
 169         struct libusb_transfer *transfer;
 170
 171         transfer = libusb_alloc_transfer(0);
 172         transfers[xferIndex] = transfer;
 173         if (!transfer) {
 174             err = LIBUSB_ERROR_NO_MEM;
 175             goto cleanup;
 176         }
 177
 178         libusb_fill_bulk_transfer(transfer, ftdi->usb_dev, ftdi->out_ep,
 179                                   malloc(bufferSize), bufferSize,
 180                                   ftdi_readstream_cb,
 181                                   &state, 0);
 182
 183         if (!transfer->buffer) {
 184             err = LIBUSB_ERROR_NO_MEM;
 185             goto cleanup;
 186         }
 187
 188         transfer->status = -1;
 189         err = libusb_submit_transfer(transfer);
 190         if (err)
 191             goto cleanup;
 192     }
 193
 194     /* Start the transfers only when everything has been set up.
 195      * Otherwise the transfers start stuttering and the PC not
 196      * fetching data for several to several ten milliseconds
 197      * and we skip blocks
 198      */
 199     if (ftdi_set_bitmode(ftdi,  0xff, BITMODE_SYNCFF) < 0)
 200     {
 201         fprintf(stderr,"Can't set synchronous fifo mode: %s\n",
 202                 ftdi_get_error_string(ftdi));
 203         goto cleanup;
 204     }
 205
 206     /*
 207      * Run the transfers, and periodically assess progress.
 208      */
 209
 210     gettimeofday(&state.progress.first.time, NULL);
 211
 212     do
 213     {
 214         FTDIProgressInfo  *progress = &state.progress;
 215         const double progressInterval = 1.0;
 216         struct timeval timeout = { 0, ftdi->usb_read_timeout };
 217         struct timeval now;
 218
 219         int err = libusb_handle_events_timeout(ftdi->usb_ctx, &timeout);
 220         if (err ==  LIBUSB_ERROR_INTERRUPTED)
 221             /* restart interrupted events */
 222             err = libusb_handle_events_timeout(ftdi->usb_ctx, &timeout);
 223         if (!state.result)
 224         {
 225             state.result = err;
 226         }
 227         if (state.activity == 0)
 228             state.result = 1;
 229         else
 230             state.activity = 0;
 231
 232         // If enough time has elapsed, update the progress
 233         gettimeofday(&now, NULL);
 234         if (TimevalDiff(&now, &progress->current.time) >= progressInterval)
 235         {
 236             progress->current.time = now;
 237             progress->totalTime = TimevalDiff(&progress->current.time,
 238                                               &progress->first.time);
 239
 240             if (progress->prev.totalBytes)
 241             {
 242                 // We have enough information to calculate rates
 243
 244                 double currentTime;
 245
 246                 currentTime = TimevalDiff(&progress->current.time,
 247                                           &progress->prev.time);
 248
 249                 progress->totalRate =
 250                     progress->current.totalBytes /progress->totalTime;
 251                 progress->currentRate =
 252                     (progress->current.totalBytes -
 253                      progress->prev.totalBytes) / currentTime;
 254             }
 255
 256             state.callback(NULL, 0, progress, state.userdata);
 257             progress->prev = progress->current;
 258
 259         }
 260     } while (!state.result);
 261
 262     /*
 263      * Cancel any outstanding transfers, and free memory.
 264      */
 265
 266  cleanup:
 267     fprintf(stderr, "cleanup\n");
 268     if (transfers)
 269        free(transfers);
 270     if (err)
 271         return err;
 272     else
 273         return state.result;
 274 }
 275